I see the retrobright community as pure OCD. Just leave it as it is. Yellow is cooler. It shows vintage class.
Agreed. Most antiques, you want to keep the patina, right?
How plastic can rust, sort of
21–29 of 29 posts
Re: How plastic can rust, sort of
#22I wonder how hydrogen peroxide (a strong oxidant) can reverse the yellowing of plastics, if the yellowing is the result of oxidation. I'm not a chemist, but this doesn't seem to make sense.
I am not a chemist, but the following comment from a retr0bright video[1] claims that retr0bright works not by reversing the process, but by speeding it up.
Interestingly, The idea that the yellowing is from the Brominated Flame Retardants in the plastic is actually itself a myth. It's a sort of believable just-so story because people look up bromine, see it is brown, and go "ah, makes sense". The interaction doesn't actually involve the brominated Fame Retardants, and is a breakdown of the butadiene chain of the plastic polymer which is effectively an oxidization which is catalyzed by energy (whether light (UV being the most energetic), or Heat). This happens with All ABS plastics, including those that don't have any Tetrobromobisphenol-A. This is why UV Stabilisers and absorbers tend to be a common inclusion in the formula of ABS plastic. (And why when they are forgotten/omitted you see things like car recalls due to seatbelt fasteners degrading). The yellowing is effectively the molecular debris from that breakdown, which gives a colour to the plastic. Hydrogen Peroxide is a strong oxidizer- it works in retrobrite not by reversing the process, but actually speeding it up. It reverses the colour change because while it significantly speeds up the butadiene being broken down, it also breaks down the molecular debris that results from it, to smaller, colorless compounds. It will also interact with other compounds in the plastic- for example, those that might have been added for the factory colouring.The result is that the colour of the original plastic returns- possibly without any factory set colouring compounds as well. Another downside is that because the butadiene chain is still compromised, retrobrite can never restore the structure of the plastic, so it will remain brittle. I've seen suggestions that an acid might be able to chemically recompose the butadiene polymer. I was able to successfully test a paste of Oxalic Acid, without any sunlight exposure for example- though it took a week and the colour change was very small.
This might explain why direct sunlight can brighten plastic instead of yellowing it even more.
Re: How plastic can rust, sort of
#23I see the retrobright community as pure OCD. Just leave it as it is. Yellow is cooler. It shows vintage class.
Agreed. Most antiques, you want to keep the patina, right?
I think the reason for "keep the patina" is actually because if you try to remove it then you will inevitably damage the underlying material.
e.g., a very skilled art restorer can remove discolored varnish
Re: How plastic can rust, sort of
#24In the wetshaving community "butterscotch" shaving brushes became sort of a sought-after commodity. They're basically plastic brushes originally meant to mimic ivory in color that have oxidized to a sort of butterscotch color.
Originally there was a lot of interest in restoring them to their original ivory-like color. If you search there's lots of advice on this, like exposing them to sunlight, or using UV lights and/or peroxides.
Eventually though I think there got to be an interest in the aged color, and interest in restoring the color declined.
I'm not a dentist, but I have family who are, and they explained similar processes are involved in teeth whitening. Basically a peroxide gel that gets put on the teeth with a custom fitting, and then exposed to UV light.
Re: How plastic can rust, sort of
#25This is done with Lego bricks as well. It may weaken the plastic to some degree. For larger pieces of plastic it shouldn't be a problem though.
Maybe someone here can explain me something.
I dug up my old duplo blocks from around 1980. Most colors are ok. The blue ones, however, have all gone brittle.
Is this normal? Why only blue?
Re: How plastic can rust, sort of
#26I've only heard of retr0bright in this regard. SNES consoles are pretty famous for yellowing at different rates. As other commenters have stated, sunlight degrades plastic. It may perform some whitening, but you're damaging the old electronics. https://www.retr0bright.com/make.html
I don't think you are supposed to apply it to the electronics. Only the plastics.
Re: How plastic can rust, sort of
#27several years back there was an article where someone methodically tried several compounds to restore yellowed plastics (IIRC it was the fire suppressant in the plastic that caused the discoloration) person put a lot of work into finding a solution. Wish I could find the article. It was a great read - cleverness, hardwork and the scientific method.
http://www.mountainouswords.com/mountain-air/retr0bright-res... http://www.retr0bright.com/
yes! thanks
Re: How plastic can rust, sort of
#28I see the retrobright community as pure OCD. Just leave it as it is. Yellow is cooler. It shows vintage class.
A yellowed SNES is just a Legend of Zelda edition.
Re: How plastic can rust, sort of
#29I suspect a lot of these electronics are intended for indoor use and are not made of UV stabilized plastics. I'd rather have yellowed electronics than ones made brittle by being left outside in the sun.
Observationally heat seems to make plastics more brittle than sunlight. Top of dash car parts seem about as brittle as shaded bottom of dash car parts. Field service people seem to kill laptops in a couple years, although we're talking about hours long process not years so that shouldn't matter, anyway I don't recall the exposed tops of their laptops being worse than the bottoms of their laptops. The scientific debat…
Yeah working on old Macs all the internal plastics (screw standoffs, drive tray clips etc) are also super brittle so I’d say heat more than light